For the purposes of covering or constructing external surfaces of buildings there are widely used components in the form of modular panels that can be put together, which must present good characteristics of tightness to infiltration, thermal insulation and mechanical resistance. The structure of said panels typically consists of a layer of insulating material, for example, fibreglass or polyurethane resin, set between two metal sheets. Said structure must enable a good modularity to be achieved, understood as the possibility of coupling a number of panels to one another to obtain a continuous covering surface. For this purpose, the panels are usually rectangular and are prearranged for being coupled alongside one another, along the respective long sides. Said structure must moreover enable panels to be made of dimensions very different from one another, without causing thereby significant modifications in the production cycle, which is preferably a cycle of a continuous type.
The interest in renewable energy sources has in recent times assumed increasing importance, above all with reference to the exploitation of solar energy via photovoltaic devices. As is known, the operation of photovoltaic devices is based upon the capacity of some appropriately treated semiconductor materials (for example, silicon) for converting the energy of solar radiation into d.c. electrical energy, without any need for mechanical parts in motion. The basic component of a photovoltaic system is the photovoltaic cell, and a number of cells assembled and connected together in a single structure form a photovoltaic module. The most common modules consist of 36 cells connected in series, assembled between a top layer of glass and a bottom layer of plastic material (usually Tedlar), and enclosed within a metal frame, usually made of anodized aluminium. The structure thus formed is strong and is able to guarantee many years of operation. In the rear part of the module there is usually located a so-called junction box, in which electrical components, such as diodes, fuses, overload-protection systems, etc., are housed, as well as contacts or terminals for electrical connection of a number of modules in series or in parallel. According to the voltage desired for the system, a number of modules can be connected in series, in a so-called “string”. The electric power requirement then determines the number of strings to be connected in parallel for providing a photovoltaic generator. The transfer of energy from the photovoltaic system to the electrical loads usually occurs through additional devices, necessary, for example, for accumulating, transforming, and/or adapting the direct current produced by the photovoltaic modules to the requirements of the end user. An essential component in this sense, if, that is, the loads have to be supplied with alternating current, is the inverter, a device that converts the direct current at output from the photovoltaic generator into alternating current.
At the current state of the art, the provision of a photovoltaic generator on surfaces of a building formed using prefabricated insulating panels of the type referred to previously entails some problems.
In the first place, the various photovoltaic modules necessary for formation of the generator call for an adequate supporting framework, the components of which must, for example, be designed according to the characteristics of the roof. Once made, said components must be assembled together, in order to obtain the framework, and anchored on the roof. This is followed by the installation of the various modules on the framework, as well as the execution of the necessary electrical connections of the various modules in series or in parallel.
The consequence of said known art is that the operations necessary for installation and anchorage of the framework, for installation of the various modules on the framework, and for electrical connection of the modules must be performed directly on the roof of the building, or in any case in sub-optimal working conditions and frequently in conditions of potential danger. The fact that the persons responsible for carrying out installation find themselves operating in such critical conditions is detrimental to the speed and quality of pre-arrangement of the system. This results basically in an increase in the times and overall costs of installation of the photovoltaic system.